[FIX] database: wait_for_connection

Now we wait some time, to make sure odoo DB is up, because in some
cases postgres can be just starting and marabunta would try to connect
too soon, getting connection refused error!

[BRANCH] bugfix-wait-db-conn-ala

maraplus/core.py

@@ -4,13 +4,16 @@
 from marabunta import parser as parser_orig
 from marabunta import model as model_orig
 from marabunta import runner as runner_orig
-from marabunta import database as database_orig
+from marabunta.database import MigrationTable
 from marabunta import web as web_orig
 
 from .config import Config, get_args_parser
 from .parser import YamlParser
 from .model import Version, VersionMode
 from .runner import VersionRunner
+from .database import Database
+
+TIMEOUT = 10
 
 
 def migrate(config):
@@ -41,8 +44,9 @@ def migrate(config):
     )
     migration = migration_parser.parse()
 
-    database = database_orig.Database(config)
-
+    database = Database(config)
+    # Wait to make sure connection is up before using it!
+    database.wait_for_connection(TIMEOUT)
     with database.connect() as lock_connection:
         application_lock = core_orig.ApplicationLock(lock_connection)
         application_lock.start()
@@ -63,7 +67,7 @@ def migrate(config):
             # migration
 
         try:
-            table = database_orig.MigrationTable(database)
+            table = MigrationTable(database)
             runner = runner_orig.Runner(config, migration, database, table)
             runner.perform()
         finally:

maraplus/database.py

@@ -0,0 +1,27 @@
+import time
+import psycopg2
+
+from marabunta import database as database_orig
+
+
+class Database(database_orig.Database):
+    """Database subclass to allow waiting for open DB connection."""
+
+    def wait_for_connection(self, timeout):
+        """Wait for given connection specified amount of seconds.
+
+        Args:
+            timeout (int): number of seconds to wait till connection
+                opens up.
+        """
+        start_time = time.time()
+        while (time.time() - start_time) < timeout:
+            try:
+                conn = psycopg2.connect(**self.dsn())
+                conn.close()
+                return True
+            except psycopg2.OperationalError:
+                pass
+            time.sleep(1)
+        # Timed out.
+        return False